The invention relates to the opening of devices with two bodies locked by latching, and notably to the opening of devices for the microbiological examination of a liquid sample under pressure.
Through French patent applications 2 802 942 and 2 802 943, such a device which has an intake body, a filtering membrane and a drainage body is already known. The intake body has a reservoir, in one wall of which a liquid inlet orifice is provided, the membrane closing off this reservoir, the drainage body being designed to support the membrane on the opposite side to the reservoir and being provided with a liquid outlet orifice, the intake body and the drainage body locking on each other by means of latching in the axial direction, the membrane being gripped annularly at the periphery between an annular transverse wall of the drainage body situated around means with which this body is provided for supporting the membrane and the lateral wall of the reservoir of the intake body, which lateral wall has an elastomer joint which forms the edge and through which this wall comes into contact with the membrane, this joint, although it is present on only one of the faces of the membrane, making it possible to obtain a seal on the two faces of the latter, because of the simple fact that the above mentioned two walls grip the membrane.
The taking of a sample to be examined is effected by connecting the inlet orifice of the reservoir of the intake body to a pressurised liquid source, so that the reservoir fills with this liquid, which can leave it only through the filtering membrane, this liquid being recovered on the other side of the membrane by the drainage body and discharged out of the latter through the outlet orifice. The latching means in the radial direction, serving to lock the intake body and the drainage body to each other, have, on the intake body, a plurality of axially oriented projecting latching tabs and, on the drainage body, a transversely oriented wall and provided for each latching tab with an aperture through which this tab can pass, the transversely oriented wall being connected to a cylindrical wall which the latching tabs face when the intake body and the drainage body are locked on each other. To prevent the withdrawal of each latching tab which has passed through an aperture in the transversely oriented wall, there is provided, on this wall, an axially oriented tooth bordering the aperture on the cylindrical wall side and, on the latching tab, a groove adapted to house this tooth.